In optical transmission devices including optical waveguides, it may be necessary to measure and modify attenuation in an optical waveguide and the relationship between the operating parameters of devices used at an input and an output of the waveguide. Testing of equipment using such optical waveguides and the setting of input or output equipment depending on the attenuation characteristics may well be costly in both time and expense.
It is an object of the present invention to provide an improved method and apparatus of matching the attenuation of an optical waveguide with the operating characteristics of apparatus used at the input and/or output ends of the waveguide.